The Australian Tax Office will work with the US and Britain to target tax dodgers after a massive cache of bank account data from tax havens was leaked to authorities.

The three nations are sharing the huge trove of data on accounts in Singapore, the British Virgin Islands, the Cayman Islands and the Cook Islands.

The information came from a leaked 400-gigabyte cache of data of more than two million documents.

It shows the activities of trusts and companies in the four countries, each of which hosts a substantial tax-free offshore banking industry offering secrecy to account holders.

The ATO says it has discovered 100 Australian names within the data and two cases have already been referred for criminal investigation.

Britain says the data has helped identify more than 100 Britons who have been hiding money in offshore tax havens.

"This data is another weapon in [the British tax authorities'] arsenal," finance minister George Osborne said.

"The message is simple: if you evade tax, we're coming after you."

International cooperation

The ATO and their British and American counterparts have not said how they obtained the data or which banks are involved.

But they have offered to share the data with other countries interested in cracking down on tax avoidance by their own nationals.

"This is part of a wider effort by the IRS and other tax administrations to pursue international tax evasion," said Steven Miller, the acting commissioner of the US Internal Revenue Service.

"Our cooperative work with the United Kingdom and Australia reflects a bigger goal of leaving no safe haven for people trying to illegally evade taxes."

Germany's finance ministry has been offered the data and says it will use it.

"What is particularly important is that with this exchange of data and this international cooperation, it will be possible to discover and fight the very complex tactics and operating modes [of tax evasion]," it said in a statement.

'Spreading aggressively'

Scandals of officials and wealthy executives stashing cash and businesses stockpiling profits in tax-free and secret accounts offshore have erupted in the United States, France, Greece, Germany, Britain and elsewhere.

In April, the Group of 20 leading economies endorsed for the first time a program to move toward the automatic exchange of banking information in an effort to end tax evasion supported by bank secrecy.

A senior US Treasury official said earlier this week that the issue would be on the agenda of the two-day G7 finance chiefs meeting that began near London on Friday.

While the source of the data held by the three countries was not revealed, the International Consortium of Investigative Journalists said it believed the records included those obtained by its journalists and publicised last month - a 260-megabyte horde of extensive account details, some from Singapore-based wealth manager Portcullis TrustNet.

Those records "illustrate how offshore financial secrecy has spread aggressively around the globe, allowing the wealthy and the well-connected to dodge taxes and fuelling corruption and economic woes in rich and poor nations alike," the ICIJ said.

Gerard Ryle, the director of ICIJ, said he was not sure why the three countries made their announcement a month after the group released its data.

"There's a lot of pressure across Europe to do something about tax havens," he told AFP.

"The leaders have to be seen as doing something because the public is really angry about what they've been reading."